Correctly Treated Garbage a Valuable Pig Food

New Zealand Journal of Agriculture, Volume 87, Issue 3, 15 September 1953, Page 197

Correctly Treated Garbage a Valuable Pig Food

GARBAGE, which is defined by the Stock Diseases Regulations 1937, Amendment No. I, as being meat scraps, discarded meat, meat offal, or kitchen or camp waste, is a useful and valuable food for the feeding of'pigs, but it can be dangerous unless handled correctly. In this article by J. C. Cooper, Livestock Instructor, Department of Agriculture, Auckland, the value of garbage as a pig food is discussed and advice on its 1 treatment is given.

THE feeding of farm animals is so closely correlated with the differences ' in structure a of the digestive tracts of these animals that practical precautions in the feeding of stock must be based on these structural differences. ' . Farm stock are. herbivorous animals which can be divided into two classes, those that chew the. cud (ruminants) and those that do not (non-ruminants). Sheep and cows are examples of ruminants. Pigs are non-ruminants. The ruminants differ chiefly from the non-ruminants in having a very complex stomach, consisting of four compartments, the rumen or paunch, the reticulum or honeycomb bag, the omasum, and the abomasum or true stomach. The paunch is large and is a store for the grass and other foods hastily swallowed by the sheep or cow. Food from the paunch is regurgitated in small wads into the mouth, where it is chewed and mixed with saliva. Subsequently it is broken down by enzymes (types of fermenting agencies) and bacteria in the paunch. . ' This bacterial digestion of fibre in the paunch is the fundamental difference between ruminants and nonruminants, such as pigs, food for which must not be unduly fibrous but must be similar to human food and be readily digested. . . ‘ The approximate capacity of the stomach of the cow is .43 gallons, of the sheep 5 gallons, and of the pig 2 gallons. , Briefly, the pig has a small digestive tract and stomach and is not provided with adequate means of dealing with coarse, fibrous fodders. The diet of the pig should consist therefore of

nutritious concentrated' foods such as cereal grains, meals, or garbage of suitable quality, supplemented with green fodder or roots. On the other hand pigs can utilise large quantities of liquid food, provided the nutrients contained in such foods are easily digested. To assist the relatively weak digestive • system of the pig, foods may be soaked or cooked. Garbage, therefore, if fed correctly, is an excellent pig food. Types of Garbage Different consignments of garbage from the same source are likely to vary from day to day, though these variations usually do not have ? a material influence on the character of the garbage. However, frequently there are fundamental differences in the character of garbage from different sources. The constituents of garbage can be divided into three groups: 1. Roughages such as greens, potatoes, and vegetable peelings and trimmings. 2. Concentrates rich in carbohydrates (sugars) but with a low fibre and protein content, such as bread and puddings. 3. Concentrates with high protein content, such as meat, meat offal, and fish scraps. The character and value of garbage depend on the amounts of the above three types that it contains, and it is convenient to recognise three grades

which differ materially in feeding value. Grade A ■ •' Grade A garbage consists chiefly of roughage such as surplus vegetables, potatoes, and cabbage leaves and other vegetable scraps collected from fruit shops, hotels, etc. This type of garbage can form part of the ration for all pigs, but it is too fibrous to be good food for young pigs. It is more suitable for large pigs and pregnant sows. . Pigs do not fatten on this grade of garbage, but it can form a large part of the ration for pigs of over 601 b. liveweight. Grade B Grade B garbage consists mainly of roughages which comprise 70 per cent, of the bulk, the remainder being of concentrates rich in carbohydrates and having a low fibre and protein content. This type of garbage is usually collected from restaurants, canteens, etc. This grade of garbage can be fed to all types of pigs, but for breeding sows and young pigs it . should be supplemented by a meal mixture which has a high’ protein content. The pigs should also receive fresh green food. Grade C ' . ... Grade C ' garbage contains both types of concentrates—those rich in sugars and those with a high protein content. They usually' form 50 per cent, of the bulk. The remainder is

made up of roughage such as potato peelings, which have-'a low fibre content. This type of garbage often does not contain sufficient roughage to be a good. pig food. It is the usual type used for pig feeding in New Zealand. Grade C is a highly concentrated food and is commonly fed alone to all types of pigs. Such pigs grow very rapidly and look well, but digestive troubles are liable to cause losses. The incidence of digestive upsets can be reduced by feeding a ration of fresh green stuff. A balanced pig ration must include:— Fats and sugars, to supply energy for all body functions, movement, growth, and production. Proteins, to maintain growth.* Minerals, for bone formation and other essential functions. Vitamins, to maintain health and constitution. Water. Broadly these requirements are met by a mixed diet of adequate quantity and variety. Garbage usually provides such a diet. - The pig’s digestive system is similar to that of human beings, and as garbage is mainly kitchen waste, it provides all the ingredients for a balanced diet. ‘ Variations in Quality There are wide differences of opinion on the value of garbage as a food for pigs. This is a result of considerable variation in the quality of it, which depends on the source and whether or not it has been specially sorted for pig feeding. Military . camps and hotels which sort their garbage for the convenience

of a contractor provide the best source of supply. Garbage from restaurants, hospitals, and other institutions is usually less rich in protein and therefore of lower feed value. Some types of unsorted municipal garbage contain large proportions of cinder and other inedible material and are valueless for pig feeding. Henry and Morrison (U.S.A. 1923) say that 1 ton of average municipal garbage will produce 401 b. of pig meat; Woodman (1941) found in carefully controlled feeding trials in England that 1 ton produced 1101 b. of pig meat. This indicates the extent of differences in the average values of swill. There are also considerable variations from day to day in garbage from the same source, variations in the fat content being most important. Care is necessary to ensure that digestive upsets are not caused by these changes, and herein lies the art of feeding this material. The table below, from Thomas and Hargrave (1931), gives the average composition of raw swills collected from various sources in Newcastle-on-Tyne, England. Figures such as those shown in the table would vary according to the day-to-day variation in swill.

Garbage Must be Boiled As most food scraps are already cooked when collected from hotels and other institutions, some pig owners consider that re-cooking such a bulk of material creates a great deal of unnecessary work, and consequently there is a strong temptation to feed garbage direct to pigs. Such action does not only constitute a breach of the Stock Diseases Regulations 1937, but is wasteful and dangerous. The danger of the introduction into this country of infectious animal diseases due to viruses has increased greatly with the expansion in recent years of fast air services and because of faster sea transport. Though quarantine regulations provide protection from direct infection by imported animals, by garbage from ships in ports, or from aircraft landing in New Zealand, the possibility of meat which could be infected being smuggled ashore or of food from overseas aircraft being pilfered cannot be overlooked. Despite all precautions, such offences may occur, and the safest precaution is to make certain that all garbage fed to pigs is boiled properly. „ . It was for this

reason that the Stock Diseases Regulations 1937 were amended in 1943. Under the Stock Diseases Regulations 1937, Amendment No. 1, a person desirous of collecting scraps from hotels or othe r institutions for feeding

to pigs must first apply to the Department of Agriculture for a permit to acquire garbage. Before such a permit is issued the applicant , must install the following equipment for the treatment of garbage:— • 1. A steam generating plant capable of raising the temperature of garbage to 212 degrees F. and of maintaining that temperature for not less than 1 hour; or 2. A boiler or boilers of such capacity that the quantity of garbage received by the applicant daily can be boiled effectively for 1 hour. .The regulations define boiling thus: To bring the garbage up to a temperature of 212 degress F. and to maintain it at that temperature for 1 hour. To heat it to any temperature below 212 degrees is not satisfactory for destroying all disease organisms. Steam Preferable Where steam pressure is used for the boiling of garbage no difficulty is experienced in carrying out the work effectively, easily, and at a low fuel cost, but where ordinary open boilers fired from below and often standing in the open are used the treating of garbage in accordance with the regulations is most difficult and expensive, both in time and fuel. Steam Plants Where a large quantity of garbage is handled the most suitable steampressure plant is a steam boiler (horizontal preferably) of not less than 3 h.p. which is capable of operating at 1001 b. of pressure, is automatically water-fed, and is oil fired with electric fan draught. A similar plant has been installed on the pig farm of Messrs. Hood and Rowe Limited at Ramarama (25 miles from Auckland), who collect garbage from a military camp and feed about 500 pigs. The pig houses are constructed with concrete floors and each house is supplied with a concrete trough running the full width of the

house. The houses are built in two rows, each facing the other, between which is laid a tramway on which runs the trolley conveying the cooked garbage from one end of the piggery to the other. A similar layout is shown in the diagram below. The plant for treating the garbage consists of an 8 h.p. horizontal steam boiler which is capable of developing a pressure of 2001 b. At present this

plant handles approximately 300 gallons of garbage daily, but it can handle considerably more. Two large concrete vats are provided and each vat is independently connected at the bottom with the steam pipe from the boiler, the pressure of steam allowed into the vat being controlled by a steam pressure • cock. Two vats are necessary where garbage is collected daily to allow one vat to cool off for feeding. The vats are emptied into the feeding trolley by a circular door let into the end of each vat and operated by a lever to control .the flow of boiled garbage. Small Pressure Boiler There is at present on the market a small steam pressure boiler which is very suitable for the sterilisation of garbage up to about 300 gallons at one time. This is a vertical type oil-fired boiler capable of generating 251 b. of steam. This boiler costs approximately £l7O. At an extra cost of approximately £25 it can be fitted with a device for automatically replacing the water evaporated. It can then be used continuously without having to be “blown down” for refilling. This type of boiler is very economical, in fuel consumption and does the job quite well. Where a large quantity of garbage is handled it is advisable, of course, to have a larger boiler to save time, as smaller boilers take about 1 hour by the time the boiler has generated sufficient steam to bring a container holding 300 gallons to boiling point. This means that 2 hours are taken to treat this quantity of garbage, because to comply with the provisions of the Stock Diseases Regulations, garbage must be held at boiling temperature for 1 hour.

Steaming in Drums One good method of treating garbage is to steam it in the drums' in which it is collected. A loading platform of sufficient size to hold the drums containing one day’s collection is placed near the boiler house and a steam pipe lagged with asbestos is led out over the platform. Dropper pipes, with their - lower ends bored with a number of holes for dispersal of the steam and having flexible pipe connections with the main steam pipe, are inserted to the bottom of each drum containing’ garbage. All the drums are then well covered with sacks and the steaming allowed to continue for 1 hour, after which the steam is turned off and the drums can be emptied individually into the feeding trolly. During cooling any surplus fat comes to the surface and can then be skimmed off before feeding is proceeded with. . ■ ' After being emptied the drums are scrubbed out and steam sterilised. A lay out suitable for this method of handling garbage is shown in the diagram at the top of . the next page. For any type of steam boiler or other steam pressure, vessel in which steam is used above atmospheric pressure a certificate issued by the Marine Department must be obtained. Trea+inq in Boilers ' On piggeries where a small quantity of garbage is used and where a steam pressure outfit is not warranted the

most suitable boiler is a circular type of heavy steel construction securely bricked in to the top in such a way as to allow the flames from the firebox below to fan up the sides of the boiler. The garbage-must be frequently stirred or agitated from the bottom by a paddle to prevent burning and to ensure that any raw meat scraps are properly cooked. In any type of open boiler stirring is essential. During a test made on boiling garbage it was found that. raw meat boiled in a large bulk of garbage failed to cook when the mass was not stirred. About 300 gallons of garbage containing two large pieces of loin of mutton were boiled without , being stirred in a square tank for 1| hours. When the mutton was removed and allowed to become cold it was difficult to tell it from raw mutton. It was returned to the boiler with the garbage boiled on the ,f oilowing day. After 1 hour’s boiling and frequent stirring, the mutton was properly cooked. ■ . Discarded square water tanks are used on some piggeries for the boiling of garbage, but they are most unsuitable, especially where daily boiling of garbage is necessary,' as the. material of which they are constructed is not meant to withstand the constant high heat required to boil garbage daily. In such tanks not only does garbage burn severely at the bottom, but tank bottoms burn through after . a few months. Further, a square . vessel makes proper agitating difficult if not impossible.

Proper Housing Whatever plant is provided to treat garbage it must be properly housed in a weatherproof shed. To attempt to boil garbage and especially to hold it at boiling temperature for 1 hour, as required by the regulations, in a boiler exposed to the weather is ridiculous. Feeding Methods Fruit and vegetable wastes, which are valuable sources of vitamins A and C, may with advantage be fed raw to pigs. If this practice is followed, however, they must .be kept separate during collection and afterward from garbage containing meat scraps, as the definition of garbage in the regulations is . such that if fruit and vegetables come in contact with meat, meat scraps, meat offal, or kitchen and camp waste the whole must be boiled. Potatoes should always be cooked, as their food value is then increased by a third. Raw unripe potatoes cause dietetic upsets. Sprouted potatoes are particularly dangerous and any sprouts must first, be broken off and discarded, as they contain the alkaloid poison solanin. Garbage which has been boiled is a much safer food than uncooked swill, it goes further, and is more digestible. Excess Fat Harmful Fat is most important in pig nutrition, because the type of fat which a pig consumes decides the solidity of the fat in the animal’s body. Fat is the most concentrated heat-giving and fat-forming food ingredient; lib. of fat

liberates in the body as much heat or energy as 2 to 2-J-lb. of either sugars or proteins. Thus on a weight basis tallow is worth at least twice the price of meal or grain. Mixtures which constitute garbage usually supply sufficient fat for pigs. The feeding of excessive quantities of fat is harmful to pigs and is wasteful. It clogs up the digestive system and much is excreted in the animals’ droppings. ' - This is an important reason for boiling garbage. Garbage ■ often contains excessive quantities of fat, and when the garbage is boiled V all fats come to the top of the boiler. If this mass is skimmed off, the amount of fat fed to pigs can be controlled. The feeding value of garbage is influenced considerably by the amount of water used in cooking. Only sufficient water should be added before cooking to ensure that all the constituents are floating. This is necessary to simplify cooking and, where a copper or similar container is used, to prevent food burning at the bottom of the boiler. - Some pig producers who use -garbage find that to handle the , bulky mass of food it is necessary to' add a large quantity of water to the garbage. ' Though this makes the food easy to handle, an excessive amount of fluid in the diet is harmful to young pigs such as weaners. They become pot bellied and unthrifty, *. and often too much fluid induces scouring. Bulky fibrous food is also detrimental to young pigs, but garbage other than grade A (see page 197), is usually satisfactory in this respect. Pigs should be fed garbage regularly (small pigs three times daily and large pigs twice) and pigs should never be allowed .to gorge. In creep feeding of suckers a little fresh garbage should be - kept constantly in.front of the litter to prevent gorging or undue fasting. :■ .'. ... . Ample trough room should be provided, about Ift. of trough , per large Pig-

As a basic, food for pigs garbage such as that from hotels and eating houses is . considered the' best protein food obtainable apart from milk products such as skimmed milk and buttermilk. An advantage which. garbage feeding has over feeding based on milk by-products is that the supply and quality of garbage does not vary greatly with the season, whereas pigs fed on dairy by-products may have to rely on a ration low ' in protein when the dairy herd is out of production, unless meat meal is . used. ' It is considered that 1| gallons of boiled garbage of the concentrated type together with greens and fresh water should be sufficient for the daily needs per pig being fattened. One farmer who uses garbage estimates that 8 gallons of boiled garbage daily and greens will feed 1 sow and fatten her progeny. This might be a satisfactory basis on which to estimate the number of breeding sows and fattening pigs which , could be carried on a certain quantity of garbage collected daily.

Growth and Carcass Quality With high-quality garbage containing meat scraps and the soup from the cooking of. these good growth is obtained without supplementing the food in any way. Lower-quality garbage must be supplemented by a meal mixture for suckers in the creep and newly weaned pigs until they have become accustomed to their somewhat bulky diet. After the porker stage is reached pigs usually do very well on garbage and this is an incentive to take them on to heavy baconer weights. However, they tend to develop soft fat and such carcasses are a problem to the bacon curer. For baconer production a substantial part. of the finishing ration should consist of barley meal or coconut 'meal, as this will assist in producing a firmer fat. Porker Production Favoured The best system -is to breed at the piggery all the pigs required and to

aim at turning off all pigs as porkers of not more than 901 b. dressed carcass weight. High-quality pork carcasses will be produced, which generally is the most profitable form of pig production. Prevention of Disease , As garbage is almost a balanced diet for pigs, some common pig ailments associated with nutrition, such as paralysis, acidosis in sows, retention of afterbirth, rickets,' failure 'of sows’ milk supply, and infertility in boars, should seldom prove troublesome in piggeries where garbage is fed. Parasitic . Diseases - Pigs fed on garbage are less liable to lung and intestinal worms, as they are usually housed and therefore have no access to worms on pasture and soil. Vitamin A Paralysis Pigs fed for long periods on food deficient in vitamin A develop, among other troubles, a degeneration of the nerves supplying the hindquarters, which often leads to paralysis. Vitamin A paralysis is usually found in pigs confined to houses and fed rations deficient in greens. Garbage usually provides sufficient vitamin A from greens and vegetable tops. Hygiene Feeding troughs in piggeries where garbage is fed should be kept as clean as those where skimmed milk or other foods are used. Dirty, sour troughs are likely to cause scouring. Bones or other inedible materials must be collected and disposed of regularly. Garbage should never be fed on the ground, as continual feeding in this way encourages vermin and the area becomes a breeding ground for disease organisms. Apart from the fact that boiled garbage is more useful as a pig food it is also safer,’ and the feeding of raw garbage direct from collecting vehicles is

an offence. Often kitchen wastes contain rubbish such as razor blades, broken glass, or pieces of tin which if swallowed by pigs could cause losses, Overseas, methods of sieving scraps to overcome this risk have been evolved,

Where garbage has been boiled in containers and thoroughly stirred foreign matter usually sinks to the bottom and there is less risk of its finding its way into feeding troughs, especially as it is usually necessary where a small

amount of garbage is handled to bucket the garbage out of the boiler into containers to cool down before it is fed out. It is essential to the welfare of farming in New Zealand generally, that garbage should be treated before use. In some' countries it has been proved . that untreated garbage often spreads diseases such as foot and mouth disease, swine fever, vesicular exanthema, and trichinosis. In the U.S.A, raw garbage has been found to be a carrier of parasites and micro-organisms dangerous to both man and animals. Sterilisation of raw garbage is a practical method of control of disease liable to be transmitted by raw untreated garbage. Vesicular Exanthema The characteristic symptoms of vesicular exanthema are similar in the early stages of the disease to those of foot, and mouth disease and it is the opinion of U.S.A, veterinary officials that cattlemen have a vital interest, because co-existence of these vesicular diseases might mask symptoms of foot and mouth disease in the early stages.This. could allow rapid spread of infection if an outbreak happened to be foot and mouth disease. For this reason alone vesicular exanthema must not reach New Zealand.

In 1952 vesicular exanthema in pigs 'Sted^f£ had existed for fpZ raw throughout the: US.A p gs fed raw garbage were most often affected, Both trichinosis and vesicular exanthema are spread .largely by the commercial feeding of raw garbage, ... trichinosis Trichinosis, a parasitic disease which has so far not reached this country, is transmissible to humans. If undercooked pork affected with trichinae

larvae is eaten by human beings, they can contract the disease trichinosis. It is one of the widespread human diseases in the U.S.A. Swine Fever Swine fever, which occurs in pigs only, has appeared in New Zealand on two occasions, but fortunately the spread was checked before serious losses occurred. Eradication of swine, fever in Canada in the last year in which outbreaks were recorded there cost only 600 dollars, whereas in the U.S.A., where vaccination is carried out, mere control of the disease cost between 30 and 40 million dollars. Regulations almost identical with those controlling the feeding of garbage in New Zealand have been in force in Canada since 1916 and they are rigidly enforced. Swine fever has been present in the U.S.A, for 120 years. It was first found in Ohio and soon spread throughout the country. The disease remained unchecked for about 75 years, when vaccination was started as a means of checking its spread. As vaccination immunises pigs against swine fever for only about a year, the cost of continued vaccination must be very high. Garbage is a valuable pig food, but in the interests of New Zealand’s economy and to protect all types of farmers it cannot be allowed to become a menace to the health of livestock, and the regulations controlling its handling must be rigidly enforced. Investigations have shown that the raising of pigs on garbage has always been lucrative and is particularly so today because of the good prices for pig meats and the relatively low cost of feeding with garbage. It would be unfortunate if the carelessness or apathy of a few made it necessary to ban the use of garbage as a pig food. The co-operation of all concerned with the handling and treatment of garbage is needed to minimise risk of spreading diseases. Reference Books For those . desiring further information on the physiology of the pig’s digestive system the following books are recommended:—- - “Pigs: Their Feeding and Diseases”, by Allan Leslie. "Feeding Farm 'Animals”; by E. T. Halirian and F. H. Gardner. , » . “Pigs”, by V. C. Fishwick.

Warning

Under a section of the Stock Diseases Regulations 1937, Amendment No. 1, it is an offence for any person to acquire garbage for feeding to swine unless he holds a permit issued under these regulations. This regulation is necessary to prevent the introduction into New Zealand of infectious stock diseases, such as foot and mouth, disease and swine fever. The procedure to be adopted to procure a permit is set out later in this article.

Use of Offal and Dead Animals from Farms

THERE are numerous losses of stock on farms, particularly in spring, when diseases such as bloat and milk fever are prevalent. Where large quantities of carcasses or offal are available it is preferable to establish a dry-rendering digester plant, the- production being either used on the spot or put through a drier and marketed as meat meal. 1 Smaller supplies' of slaughterhouse offal can be cooked by steam as already described for feeding to pigs. If cooking is done in an ordinary copper, the blood has to be discarded, as it burns on to the copper, but blood can be used when the whole is cooked in a steam-jacketed pan or by other steam cooking methods. Offal is a much more valuable food when the blood is retained. There is usually considerable surplus of fat from offal or-carcasses and it is important to skim as much as possible of this off before the cooked offal is fed to pigs*. This tallow may be disposed of direct to dairy' farmer pig producers whose food supply is normally deficient in fat or further purified and sold elsewhere. The use of offal as pig food was described in an article "Country Slaughterhouse Piggeries" which appeared in the December 1950 issue of the "Journal".

Crude CarboMineral Source of swill swili Moisture Moisture Oil Crude Oil protein Carboprotein hydrate Fibre Mineral Fibre matter matter Raw swill: Hotel .. .. .. 76.53 - - 5.38 5.90 9.58 0.54 2.07 Restaurant .. 69.63 ‘ 5.97 5.18 16.81 0.55 1.86 First-class cafe cafe .. 79.22 . . 79.22 3.59 3.59 2.66 2.66 11.79 11.79 0.70 0.70 2.04 2.04 Second-class cafe cafe .. 68.99 .. 68.99 6.47 6.47 4.73 4.73 16.56 16.56 0.98 0.98 2.27 2.27 Dry matter of swill: swill: Hotel .. .. 22.91 25.14 40.84 2.31 8.80 Restaurant 19.66 17.06 55.36 1.81 6.11 First-class cafe , 17.29 12.81 56.74 3.36 9.80 Second-class cafe cafe 20.89 20.89 15.28 15.28 53.34 53.34 3.15 3.15 7.34 7.34

MEAN PERCENTAGE COMPOSITION OF RAW SWILLS COLLECTED AT NEWCASTLE-ON-TYNE, ENGLAND, AND ANALYSED WEEKLY OVER 6 MONTHS